u-boot: adapt to change in build directory in morty
u-boot: adapt to change in build directory in morty

In YP 2.2 (Morty) {B} is no longer the default working directory
for tasks [1]. Adapt the deploy task so it finds the srec.

[1] http://www.yoctoproject.org/docs/2.2.1/ref-manual/ref-manual.html#migration-2.2-B-no-longer-default-working-directory-for-tasks

(cherry picked from commit 08383820f1b5b7a39be5f9e47925026abeb26463)

Signed-off-by: Stephen Lawrence <4e793ced895c01a9ab00954a3eb58bff976c9ded@renesas.com>

slawr/meta-renesas,slawr/meta-renesas,slawr/meta-renesas